President Trump used an Indiana rally Thursday to soothe conservative fears that he’s going to make too many concessions to the North Koreans.

“I think it’s going to be a very big success,” Trump said of the June 12summit in Singapore with Kim Jong Un. “But my attitude is: If it isn’t, it isn’t. Okay? If it isn’t, it isn’t. … You have to (say) that, because you don’t know.”

Everyone is excited about the homecoming of the three American prisoners, but there’s growing anxiety in the national security firmament that the president might be too hungry for a big win. Trump has appeared intoxicated at times by the possibility he could win the Nobel Peace Prize and relishes the chants of “Nobel” that have become standard fare at his rallies. He’s also been ratcheting up expectations that history will be made at his summit. Announcing the time and place of his meeting with Kim, the president tweeted: “We will both try to make it a very special moment for World Peace!”

At the gymnasium in Elkhart, Ind., he returned to this theme, which was prominent in “The Art of the Deal.” “We’re not going to be walked into an Iran deal where the negotiator, John Kerry, refused to leave the table,” the president said, referring to the secretary of state who negotiated the multilateral Iran nuclear deal that he pulled the U.S. out of earlier this week.

-- Some hawkish thought leaders on the right have begun to say publicly over the past week what many more are saying privately during Washington cocktail parties: that the neophyte commander in chief could get suckered into taking a bad deal because he so badly wants to claim a diplomatic triumph.

You don't have to be "hawkish" to worry that Trump is going to screw the pooch. This isn't some negotiation over a licensing deal to manufacture cheap ugly ties in China. It isn't even a deal to put your name on some hideous sky-scraper in Azerbaijan. This is about nuclear war.

The problem is not that he's going to "walk" if it doesn't go well or if he succumbs to flattery and pretends that some worthless "agreement" has brought world peace. The problem is that the man has no idea what he's talking about and has absolutely no business personally involving himself in something this delicate and dangerous. He doesn't know what he doesn't know and he is incapable of learning because he won't listen. The stakes are too high to put an imbecile in charge of nuclear negotiations.

The South Koreans are in a better position to do this and it's possible they will be able to broker some kind of agreement and let the Big Baby take credit. That's probably the best we can hope for.